Optical system for facilitating plant growth

ABSTRACT

Optical system for facilitating plant growth is provided. The optical system can produce a light beam having a full width at half-maximum (FWHM) angle of greater than 120 degrees in one or more transverse directions, wherein the transverse direction is perpendicular to the optical axis of the light beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage entry of PCT/US2019/027887 filedApr. 17, 2019, which claims the benefit of U.S. Provisional ApplicationNo. 62/658,958, filed Apr. 17, 2018, and U.S. Provisional ApplicationNo. 62/790,721, filed Jan. 10, 2019, the contents of which areincorporated by reference herein in their entirety.

FIELD

The present disclosure relates generally to systems for improvingefficiency and yields in plant growing operations.

BACKGROUND

Indoor farming and horticultural operations where plants are grown underartificial lighting are getting more and more important in the recentyears. Some advantages of indoor plant growth operations includeallowing for extended growing cycles, increased yields per unit area,fine tuning of environmental variables including light output to enhanceplant yields, security and ability of monitoring the operation in realtime.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the disclosure are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present disclosure will be obtained by reference tothe following detailed description that sets forth illustrativeexamples, in which the principles of the disclosure are utilized, andthe accompanying drawings of which:

FIG. 1 is a diagrammatic view of an optical system and the light beamemitted by the optical system according to at least one example of thepresent disclosure.

FIG. 2A is a top view of a plurality optical systems illuminatingmultiple objects according to at least one example of the presentdisclosure.

FIG. 2B is a side view of the plurality of optical systems in FIG. 2A.

FIG. 2C is a side diagrammatic view of a plurality of optical systemsilluminating an object with the plurality of optical systems having anoptical axis deviating from horizontal according to at least one exampleof the present disclosure.

FIG. 2D is a diagrammatic side view of an optical system illuminating anobject at an angle relative to a horizontal axis according to at leastone example of the present disclosure.

FIG. 2E is a top view of an optical system illuminating two objectsaccording to at least one example of the present disclosure.

FIG. 3A is a light intensity distribution pattern and optical powerdensity distribution pattern in one or more transverse directionsaccording to at least one example of the present disclosure.

FIG. 3B is a light intensity distribution pattern and an optical powerdensity distribution pattern in a transverse direction according toanother example of the present disclosure.

FIG. 4 is a top view of two optical systems illuminating an objectaccording to at least one example of the present disclosure.

FIG. 5A is a light intensity distribution pattern in one or moretransverse directions according to yet another example of the presentdisclosure.

FIG. 5B is another example light intensity distribution pattern in oneor more transverse directions according to the present disclosure.

FIG. 5C is an optical systems illuminating two objects from aboveaccording to at least one example of the present disclosure.

FIG. 5D is a light intensity distribution pattern of optical system inFIG. 5C and/or in FIG. 2A-D.

FIG. 5E is a realized example of a light intensity distribution patternof optical system according to at least one example of the presentdisclosure.

FIG. 6 is a cross-sectional view of a lens profile and a LED profileaccording to at least one example of the present disclosure.

FIG. 7 is a cross-sectional view of another lens profile and LED profileaccording to at least one example of the present disclosure.

FIG. 8 is a cross-sectional view of another lens profile, the primaryoptics element profile and LED profile according to at least one exampleof the present disclosure.

FIG. 9 is a cross-sectional view of another lens profile, the primaryoptics element profile and LED profile according to another example ofthe present disclosure.

FIG. 10 is a cross-sectional view of another lens profile and theprimary optics element profile according to at least one example of thepresent disclosure.

FIG. 11 is an isometric view of an example of a LED, a primary opticselement and a lens according to at least one example of the presentdisclosure.

FIG. 12 is an isometric view of another example of a lens and a CPC.

DETAILED DESCRIPTION

Examples and various features and advantageous details thereof areexplained more fully with reference to the exemplary, and thereforenon-limiting, examples illustrated in the accompanying drawings anddetailed in the following description. Descriptions of known startingmaterials and processes can be omitted so as not to unnecessarilyobscure the disclosure in detail. It should be understood, however, thatthe detailed description and the specific examples, while indicating thepreferred examples, are given by way of illustration only and not by wayof limitation. Various substitutions, modifications, additions and/orrearrangements within the spirit and/or scope of the underlyinginventive concept will become apparent to those skilled in the art fromthis disclosure.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,product, article, or apparatus that comprises a list of elements is notnecessarily limited only those elements but can include other elementsnot expressly listed or inherent to such process, process, article, orapparatus. Further, unless expressly stated to the contrary, “or” refersto an inclusive or and not to an exclusive or. For example, a conditionA or B is satisfied by any one of the following: A is true (or present)and B is false (or not present), A is false (or not present) and B istrue (or present), and both A and B are true (or present).

The term substantially, as used herein, is defined to be essentiallyconforming to the particular dimension, shape or other word thatsubstantially modifies, such that the component need not be exact. Forexample, substantially cylindrical means that the object resembles acylinder, but can have one or more deviations from a true cylinder.

Additionally, any examples or illustrations given herein are not to beregarded in any way as restrictions on, limits to, or expressdefinitions of, any term or terms with which they are utilized. Insteadthese examples or illustrations are to be regarded as being describedwith respect to one particular example and as illustrative only. Thoseof ordinary skill in the art will appreciate that any term or terms withwhich these examples or illustrations are utilized encompass otherexamples as well as implementations and adaptations thereof which can orcan not be given therewith or elsewhere in the specification and allsuch examples are intended to be included within the scope of that termor terms. Language designating such non-limiting examples andillustrations includes, but is not limited to: “for example,” “forinstance,” “e.g.,” “In some examples,” and the like.

Although the terms first, second, etc. can be used herein to describevarious elements, components, regions, layers and/or sections, theseelements, components, regions, layers and/or sections should not belimited by these terms. These terms are only used to distinguish oneelement, component, region, layer or section from another. Thus, a firstelement, component, region, layer or section discussed below could betermed a second element, component, region, layer or section withoutdeparting from the teachings of the present disclosure.

Optical systems described herein provide a light beam with a full widthat half-maximum (FWHM) angle of greater than one hundred twenty degrees(120°) in one or more transverse directions. The one or more transversedirection are substantially perpendicular to the optical axis of thelight beam. In some instances, the optical axis of the light beam can beperpendicular to the light emitting surface of the optical system orparallel to the central axis of the optical system. In some instances,the optical axis of the light beam is the same axis as a central axis ofthe optical system.

According to at least one example, a light spot illuminated by the lightbeam on a projection plane at a distance from the optical system can bepolygonal, circular, and/or elliptical in shape. The optical powerdensity in the light spot is substantially uniform.

The projection plane can be a plane (for example, a plant bed) locatedin the light path of the optical system and at a distance from theoptical system. A projection surface can be an area upon an objectlocated in the projection plane, and the light beam provided by theoptical system is received by the projection surface.

According to at least one example, the light beam has an FWHM anglebetween 120 degrees and 160 degrees in one or more transversedirections.

According to at least one example, the optical system is configured toproduce a light beam having an FWHM angle of greater than one hundredtwenty degrees (120°) in a first transverse direction, and having anFWHM angle of less than one hundred twenty degrees (120°) in a secondtransverse direction. The first transverse direction and the secondtransverse direction can be substantially perpendicular to each other.The optical system can be configured to produce a light beam having anFWHM angle of greater than one hundred thirty degrees (130°) in thefirst transverse direction, and having an FWHM angle of less than eightydegrees (80°) in the second transverse direction. The optical system canfurther be configured to produce a light beam having an FWHM angle ofgreater than one hundred thirty degrees (130°) in the first transversedirection, and having an FWHM angle of less than fifty degrees (50°) inthe second transverse direction. The optical system can be configured toilluminate one or more plants in a lateral direction, with the firsttransverse direction along one or more lateral sides of the one or moreplants. The optical system can be configured to illuminate one or moreplants obliquely vertically, with the angle between the optical axis ofthe optical system and a horizontal plane being greater than ten degrees(10°). The angle with respect to the horizontal direction can be greaterthan half of the FWHM angle in the second transverse direction.

According to at least one example, the optical power density in a lightspot illuminated by the light beam on a projection surface at a distancefrom the optical system is substantially uniform. The projection surfacecan be a surface of a conical body or a plane.

According to at least one example, a light spot illuminated by the lightbeam on a projection surface can have an average optical power densityon an intermediate region in the light spot equal to or less thanaverage optical power density on a first region, wherein the firstregion is an annular region surrounding the intermediate region in thelight spot. The light spot can be a portion of the projection surfaceilluminated by the light beam. In one or more transverse directions, thelight intensity of light can increase from the optical axis to theperiphery. In one or more transverse directions, the light intensitydistribution of the light beam I(θ) can be substantially equal toI₀/cos³(θ), where I₀ is the light intensity of the light at the opticalaxis and I (θ) is the light intensity of the light having an angle θrelative to the optical axis. Average optical power density on theintermediate region in the light spot can be a global minimum in thelight spot.

According to at least one example, a light spot illuminated by a lightbeam on a projection plane can comprise two or more illuminated areas,wherein each illuminated area illuminates one or more plant and/or plantpot. The light intensity distribution of each illuminated area can havea trough and two crest located on two opposite sides of the trough inone or more transverse directions. The trough can be located at alongitudinal direction having an angle θ with respect to the opticalaxis. The angle θ can be about forty five degrees (450°). One of the twocrest can be located at a longitudinal direction having an angle ofabout seventy five degrees (75°) with respect to the optical axis, andthe other of the two crest can be located at a longitudinal directionhaving an angle of about fifteen degrees (15°) with respect to theoptical axis. The average optical power density on a gap area betweentwo adjacent illuminated areas can be less than the minimum opticalpower density on the illuminated areas. The ratio of light energy on thegap area between two adjacent illuminated areas relative to the totalenergy of the light beam can be less than twenty percent (20%). The gaparea between two adjacent illuminated areas corresponds to an angle ofless than about thirty five degrees (35°).

According to at least one example, the optical system can include afirst LED array and a second LED array, wherein the optical axis of thefirst LED array and the optical axis of the second LED array extend indifferent directions. The optical axis of the first LED array and theoptical axis of the second LED array can form an angle of between twentyand one hundred twenty degrees (20-120°) between each other. The opticalaxis of the first LED array and the optical axis of the second LED arraycan from an angle relative to the optical axis of the optical system,respectively. The angle can be between from about ten degrees (10°) tosixty degrees (60°).

According to at least one example, the light beam can have spectraincluding blue wavelengths and red wavelengths.

According to at least one example, the one or more light sources caninclude at least one light source of the one or more light sourcesoperable to emit a light beam having different wavelengths, and the atleast one light source operable to emit a light beam having differentwavelengths are controllable individually.

It shall be understood that different aspects of the disclosure can beappreciated individually, collectively, or in combination with eachother. Various aspects of the disclosure described herein can be appliedto any of the particular applications set forth below or for any othertypes of movable objects. Any description herein of aerial vehicles,such as unmanned aerial vehicles, can apply to and be used for anymovable object, such as any vehicle.

Other objects and features of the present disclosure will becomeapparent by a review of the specification, claims, and appended figures

Examples described herein provide an optical system that creates a lightbeam having an FWHM angle of greater than about 120 degrees in one ormore transverse directions, wherein the transverse direction issubstantially perpendicular to the optical axis of the optical system.The optical system can be created using one or more light sources. Theterm “light source” is defined to include any element capable ofproducing a light beam (visible or invisible to the human eye)including, but not limited to, a light emitting diode (LED), a compactfluorescent light (CFL), a fluorescent, an incandescent, an infrared, ametal halide light, and/or a high pressure sodium light.

In one or more examples, the light beam(s) emitted from the lightsources are combined into one light beam and emitted. In some examples,the plurality of light sources can be arranged in an array shape,wherein the array can be a polygon shape including, but not limited to,a square array, a rectangular array, a circular array. In at least oneexample, the plurality of light sources is arranged in a plurality ofconcentric rings.

In one or more examples, the optical system further comprises one ormore optical elements for collecting, shaping, and/or uniformization ofthe light emitted from the light sources. For example, a lens or acompound parabolic concentrator (CPC) can be disposed on the lightemitting side of each light source for shaping and/or uniformization ofthe light emitted from the light source. Alternatively, multiple lightsources can share one lens or one CPC, which is used to uniformizeand/or shape the combined beams of the multiple light sources.

The optical system can produce a beam of light having a wide variety ofcomplex spectra, including, but not limited, blue wavelengths, greenwavelengths, red wavelengths, ultraviolet, and/or infrared wavelengths.Specifically, for example, the beam of light emitted by the opticalsystem comprises at least one wavelengths of 450 nanometers (nm), 575nm, 660 nm, and/or 730 nm. For example, the beam of light emitted by theoptical system comprises at least one wavelengths of 620 nm-630 nm, 640nm-660 nm, 450 nm-460 nm, 460 nm-470 nm, and 725-735 nm.

In some examples, light sources for emitting different wavelengths canbe controllable individually. Thus, light intensity of differentwavelengths can be adjusted individually.

In the description of the disclosure, the optical system produces alight beam having an FWHM angle of greater than about 120 degrees in oneor more transverse directions, wherein the transverse direction refersto a direction perpendicular to the optical axis of the light beam. Insome examples, the optical axis of the light beam is perpendicular tothe light emitting surface of the optical system or parallel to thecentral axis of the optical system. In some examples, the optical axisof the light beam is substantially the same axis as the central axis ofthe optical system. It is understood that there are numerous transversedirections. In some example, the transverse direction and the opticalaxis are in substantially the same plane.

Reference is now made in detail to the exemplary examples of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, like numerals will be used throughout thedrawings to refer to like and corresponding parts (elements) of thevarious drawings.

FIG. 1 shows an example of an optical system and a light beam emitted bythe optical system. The optical system 10 can emit a light beam 14having an FWHM angle α in a transverse direction 11. The FWHM angle α inthe transverse direction 11 can be about one hundred thirty degrees(130°) to about one hundred forty degrees (140°) or any other anglebetween about one hundred twenty degrees (120°) and about one hundredfifty degrees (150°). The transverse direction 11 can be one of thetransverse directions that are perpendicular to the optical axis 13 ofthe optical system 10.

In some examples, as shown in FIG. 1, the optical system 10 produces alight beam 14 having an FWHM angle α of greater than 120 degrees in afirst transverse direction 11, and an FWHM angle β of less than 120degrees in a second transverse direction 12. In at least one example,the optical system 10 can produce a light beam 14 having an FWHM angle βof less than 80 degrees in the second transverse direction 12. In otherexamples, the optical system 10 can produce a light beam 14 having anFWHM angle β of less than 50 degrees in the second transverse direction12. The second transverse direction 12 can be substantiallyperpendicular to the first transverse direction 11. In other examples,the first transverse direction 11 can be perpendicular to the secondtransverse direction 12.

In some examples, the light beam 14 emitted from the optical system 10can have an FWHM angle of greater than 120 degrees in all transversedirections. In this way, the light beam 14 can cover a large area sothat the light beam can simultaneously illuminate a larger number ofobjects near the optical system 10. In at least one example, the opticalsystem 10 can be operable to illuminate one or more plants.

In yet other examples, the light beam 14 emitted from the optical systemcan have an FWHM angle between 120 degrees and 160 degrees in one ormore transverse directions.

In operation, a large number of objects (for example, plants) can bearranged in a substantially rectangular shaped layout, thus having onetransverse plane extending greater than a perpendicularly orientatedtransverse plane. In at least one example, a first transverse plane 11can extend in a substantially vertical direction, and greater than asecond transverse plane 12 in a substantially horizontal direction. Inother examples, a first transverse plane 11 can extend in asubstantially horizontal direction, and greater than a second transverseplane 12 in a substantially vertical direction. In yet other examples,the first transverse plane 11 and the second transverse plane 12 canextend in any direction or orientation relative to each other. Theoptical system 10 can illuminate the objects from the top of theobjects. The optical system 10 can be arranged such that the firsttransverse direction 11 along a longitudinal arrangement direction ofthe objects, which allows the light beam 14 to cover more than oneobjects. The optical system 10 can be arranged such that the secondtransverse direction 12 is perpendicular to the arrangement direction ofthe one or more objects, which makes the light beam 14 efficiently usedin the second transverse direction 12. In some examples, the opticalsystem 10 can illuminate two plants in the first transverse direction11.

FIG. 2A is a top view of a plurality optical systems illuminatingmultiple objects according to at least one example of the presentdisclosure. Each of the one or more optical systems 20 can produce alight beam 24 operable to cover different lateral sides of an object 23.For example, two light beams from two optical systems 21 and 22,respectively, illuminate opposing sides of the object 23. In someexample, a combined light beam from one or more optical systems cancover a lateral side of a plant.

The angle α the light beam 24 provided by each of the plurality ofoptical systems 20 can be greater than 120 degrees in at least onetransverse direction. While FIG. 2A illustrates a top down view showinga substantially vertically orientated transverse plane, it is within thescope of this disclosure to implement the optical system in anyorientation and provide a light beam with an FWHM angle greater than 120degrees relative to a transverse plane. For example, the optical systemcan provide illumination from the top of an object, the bottom of anobject, or any angle therebetween.

With the multiple objects arranged in a lateral row, a lateral side ofevery two adjacent plants is illuminated by one optical system 21, andthe opposite sides of the two plants are illuminated by another opticalsystem 22. Each of the majority of plants is illuminated by fourseparate optical systems.

In some examples, the highest optical system 20 in a vertical directioncan be set at a height of about one-half to two times (0.5×-2×) theobject height (shown more clearly in FIG. 2B). In at least one example,the highest optical system in a vertical direction can be set at aheight of 1.2 times the object height. In some examples, the opticalaxis 28 of each optical system 20 lies between the two laterallyadjacent objects. The distance between an optical system 20 and thecenter of each of the two laterally adjacent objects can be about one totwo (1-2) times the object radius. In at least one example, the distancebetween each optical system and the center of each of the two plants canbe set as approximately 1.4 times the plant radius.

In some examples, each optical system 20 can be arranged such that thefirst transverse direction parallel to the horizontal direction, whichmakes the light beam from each optical system covering lateral sides ofone or more objects 23 (for example, two plants in FIG. 2A). In someexamples, the optical axes 28 of the one or more optical systems 20(shown in FIG. 2B) can be not parallel to a horizontal direction.

While FIG. 2A illustrates four objects 23 illuminated on each lateralside by two optical systems 20, it is within the scope of thisdisclosure to include any number of objects 23 in a lateral directionilluminated by any number of optical systems 20 in the lateraldirection. For example, there can be six, eight, ten, fourteen, or anynumber of objects 23 in a lateral direction illuminated by two, four,five, six, eight, twenty or any number of optical systems 20. Further,while FIG. 2A illustrates each optical system 20 illuminating twoobjects 23, it is within the scope of this disclosure to illuminate anynumber of objects 23 with each optical system 23 including, but notlimited to, one, three, four, five, six, etc. objects illuminated byeach optical system 23.

FIG. 2B is a side view of the plurality of optical systems in FIG. 2A.One or more optical systems are disposed in a vertical direction, thusilluminating a lateral side of an object 23. For example, in FIG. 2B,optical systems 21, 25, and 26 are disposed in a vertical orientation toilluminate a lateral side 27 of an object 23. The one or more opticalsystems 20 can individually produce a light beam 24 having an FWHM angleβ of less than about 80 degrees. The optical axis 28 of the one or moreoptical systems 20 can be substantially parallel to a horizontaldirection.

FIG. 2C is a side view of a plurality of optical systems illuminating anobject with the plurality of optical systems having an optical axisdeviating from horizontal according to at least one example of thepresent disclosure. The one or more optical systems 20 can be arrangedsuch that the one or more optical axes 28 forms an angle δ with ahorizontal axis 29 (shown more clearly in FIG. 2D). The one or moreoptical systems 20 can illuminate one or more objects 23 in an obliquevertical direction. The angle δ formed by the optical axis 28 and thehorizontal axis 29 can be either a positive or negative inclinationangle. For example, angle δ can be formed above or below the horizontalaxis 29.

FIG. 2D shows a side view of an optical system illuminating an object atan angle relative to a horizontal axis. The optical system 20 can beangled to produce a light beam 24 having an optical axis 28 at angle δrelative to the horizontal axis 29. The optical system 20 can be angleddownward to provide an increase illumination on the object 23. In atleast one example, the optical system 20 can be configured to illuminatea plant and the optical system can be angled downward at an angle δdetermined by the particular plant being illuminated. The angle δ can bevaried by the leaf structure, growth rate, growth pattern, and/or anyother factor of the particular plant being illuminated.

While FIG. 2D illustrates angle δ as a negative, or downward,orientation, it is within the scope of the present disclosure toimplement an optical system 20 having a positive angle δ relative to thehorizontal axis 29, thus having the optical system 20 angled upwardrelative to the horizontal axis 29.

FIG. 2E shows a top view of the optical system 30 illuminating twoobjects 23. The optical systems 20 can be arranged such that the opticalaxis 28 has an angle δ with the horizontal direction 29 (shown in FIG.2D). The optical system 20 can illuminate the objects 23 in an obliquevertical direction. The illuminating angle (angle δ) between the opticalaxis of each optical system 20 and the horizontal axis 29 can be betweenabout 10 degrees to 60 degrees. Different optical systems 20 can or cannot have the same illuminating angle, including within a singleillumination arrangement.

In some examples, the optical system 20 is configured to illuminate oneor more objects 23 with the optical axis 28 facing down and having anangle δ greater than 10 degrees with respect to the horizontaldirection. The angle δ with respect to the horizontal axis 29 can begreater than half of the FWHM angle in the second transverse direction(for example, angle β in FIG. 1). The light beam can illuminate theobject(s) 23 obliquely vertically, which is conducive to improving theutilization of the light beam 24.

In some examples, each optical system 20 can be adjustable to change thedirection of optical axis 28 in the vertical direction, such that angleδ can be independently adjustable for each optical system 20. Thus, theuser can adjust the direction of the optical system 20 to adapt todifferent heights of objects (for example, growing plants), and can alsoadjust the vertical spacing between two adjacent light spots to generatea uniform light distribution. In some examples, the angle δ between theoptical axis 28 of each optical system 20 and the horizontal axis 29 canbe adjusted to an angle between approximately 10 degrees to 60 degrees.

A light spot on a projection surface illuminated by the light beamemitted from the optical system can be of any shape. In some examples,the light spot on the projection surface is a regular pattern or anirregular pattern. For example, the projection surface can be a plane,and the light spot on the plane can be polygonal, circular, ellipticaland/or rectangular in shape. The projection surface can be a curvedsurface. For example, the projection surface can be a surface of a plant(for example, the objects in FIG. 2E). The object 23 cancan have aspherical body, cylindrical body, a circular truncated frustoconicalbody, and/or a conical body. In some examples, the conical body can havea cone angle between about 20 degrees and about 70 degrees. The lightspot described in the present disclosure can be produced by the opticalsystem illuminating the plant from above, from the side, and/or at anyangle therebetween.

The light intensity distribution of the light beam 24 can be of anypattern. The optical power density distribution pattern of the lightspot illuminated by the light beam on a projection surface can be of anypattern.

FIG. 3A shows an example of a light intensity distribution pattern andoptical power density distribution pattern in one or more transversedirections. The light spot on a projection surface (shown more clearlyin FIG. 5D and FIG. 5E) has a substantially uniform distribution ofoptical power density in the one or more transverse directions.

A substantially uniform distribution of optical power density in acertain illuminated area in the present disclosure means that themaximum optical power density is less than 10 times (or less than 5times) the minimum optical power density in the illuminated area.

The relationship between optical power density E in a light spotilluminated by a light source formed in a projection plane and lightintensity I is: E(θ)=I(θ)*cos³ (θ)/L², where θ is an angle to theoptical axis, L is a distance between the light spot and the lightsource, wherein the projection plane is any plane at a distance from theoptical system. According to the relationship between optical powerdensity E and light intensity I, in order to generate a light spothaving substantially uniform optical power density, the light intensityat the optical axis forms a substantially trough shape 35 in the lightintensity distribution 30 of the light beam in the one or moretransverse directions. In one or more transverse directions, the lightintensity I can increase from the center to the periphery. In at leastone example, in all transverse directions the light intensity canincrease from the center to the periphery.

In some examples, the distribution of the light intensity of the lightbeam I(θ) is substantially equal to

$\frac{I_{0}}{\cos^{3}(\theta)}$in one or more transverse directions, where I₀ is the light intensity oflight at the optical axis, and I (θ) is the light intensity of lighthaving an angle θ to the optical axis. The distribution of the lightintensity makes a substantially uniform distribution of optical powerdensity on the spot illuminated by the light beam in a projection planeat a distance from the optical system. A uniform distribution of opticalpower density on the spot along the one or more transverse directionscan promote similar growth rates at different locations of plants.

In some examples, the optical power density of the light beam on one ormore circles centering on the optical axis is substantially uniform. Insome examples, the optical power density of the whole light beam spot issubstantially uniform.

In some examples, the distribution of optical power density on the wholelight spot is substantially uniform. In some examples, the distributionof optical power density on a certain area of the light spot issubstantially uniform. In at least one example, the certain area islocated around the optical axis.

FIG. 3B shows another example of a light intensity distribution patternand an optical power density distribution pattern in a transversedirection according to at least one example of the present disclosure.In a light spot illuminated by the light beam on a projection plane, theaverage optical power density on a center section around the opticalaxis can be less than the average optical power density on an edgesection of the light spot in one or more transverse directions. Theaverage optical power density is equal to the total optical power of thecertain section divided by the area of the section. In the one or moretransverse directions, the optical power density of light spot canincrease from the center to the periphery.

In some examples, the shape of the light spot is circular, elliptical,close to circular and/or close to elliptical. The light spot comprises afirst region and a second region surrounding the first region. Theoptical power density on the first region is not greater than theoptical power density on the second region. In some examples, theoptical power density in the first area and/or the second area issubstantially uniform. In some examples, the optical power density onthe first area and/or the second area increases from the center to theperiphery. The first region can be located around the optical axisand/or has a distance from the optical axis.

In some examples, the shape of the light spot is rectangular orsubstantially similar to rectangular. The light spot comprises a firstregion, a second region and a third region which of both are locatedrespectively at two sides of the first region. For example, the secondregion, the first region and the third region are three strip-shapedregions in the light spot. The optical power density on the secondregion and the third region is not less than the optical power densityon the first region. Optionally, the optical power density on the secondregion is similar to the optical power density on the third region. Insome examples, the first region is located around the optical axis.

In some examples, the optical power density in the second region and/orthe third region is substantially uniform. In some examples, the opticalpower density on the second region and/or the third region can increasefrom one side close to the first region to the other side. In someexamples, the optical power density on the second region and/or thethird region can decrease from one side close to the first region to theother side. In some examples, the optical power density on the secondand third regions increases from the center to both sides.

As FIG. 3B shows, in a transverse direction, a light intensity trough 38occurs around the optical axis in the light intensity distribution, andthe light intensity increases as the angle to the optical axisincreases.

Optical systems with light intensity described above can be used toilluminate one plant from just above or from lateral side of the plant,with the optical axis of the optical system substantially going throughthe middle of the plant. The first region mentioned above can beconfigured to cover the center of the plant. The illuminated area on theplant at the optical axis is closest to the optical system. If theoptical power density on this area is higher than optical power densityon other regions, it would result in the fastest growth of the leaveslocated directly under the optical system to block the light emittedfrom the light source. The light intensity distribution in this examplecan avoid this problem.

FIG. 4 is a top view of two optical systems illuminating from opposingsides. The light beams 44 produced by the two optical systems 41 and 42each has an FWHM angle μ of greater than one hundred twenty degrees(120°) in the horizontal transverse direction, and covers two opposingsides of an object 43. In at least some examples, in the light spotilluminated by one light beam on the plant, the first region covers amiddle region 43 a of the object 43. The second region and the thirdregion of the object 23 respectively cover the edge regions 43 b of theobject 34 on either side of the middle region 43 a. In at least oneexample, the light received by leaves of a plant object 43 in the middleregion 43 a and closest to the optical system 40 can be weakened, so asto prevent the leaves from growing too fast and blocking the light beam44 emitted by the optical system 40. The optical power density on thesecond region 43 b and the third region 43 b can be substantiallyuniform, so that the leaves located on both edge sides have a similargrowth rate.

In some examples, the light spot illuminated by the light beam on aprojection plane comprises two or more illuminated areas, wherein eachilluminated area illuminates one object 43.

FIG. 5A shows another example of a light intensity distribution patternin one or more transverse directions. The light intensity distributionpattern of the light beam in the one or more transverse directions canhave an oscillating shape. The light intensity distribution can have twoor more troughs. In this example, the light intensity distribution hasthree troughs, a first trough 51 located around the optical axis, asecond trough 52 located at a longitudinal direction having an angle θ₁with respect to the optical axis, and a third trough 53 located at alongitudinal direction having an angle θ₂ with respect to the opticalaxis. The angle θ₁ can equal to the angle θ₂. The troughs can bedisposed between one or more peaks.

An optical system with light intensity described in FIG. 5A can be usedto illuminate one or more objects (for example, one or more plants) fromabove and/or from one or more lateral sides of the one or more objects.In some examples, the light spot illuminated by the light beam on aprojection plane comprises four illuminated areas, and the opticalsystem is configured to illuminate four objects. In the light spotilluminated by optical system, each trough can be located at a gap areabetween two adjacent objects, and each peak located at one object.

In some examples, the light spot illuminated by the light beam in FIG.5A on a projection plane comprises two illuminated areas, and theoptical system is configured to illuminate two plants. In the light spotilluminated by the optical system, the first trough 51 is located at agap between two adjacent illuminated areas. The second trough 52 islocated at the center of one illuminated area, and the third trough 53is located at the center of the other illuminated area.

In some examples, different troughs can have different light intensityvalues. FIG. 5B shows another example of a light intensity distributionpattern in one or more transverse directions. A trough 51 locatedbetween two adjacent illuminated areas can be lower than the other twotroughs 52, 53. The trough located between two adjacent illuminatedareas can be lower than 0.5 times any of the other two troughs.

An optical system with light intensity described in FIG. 5B can be usedto illuminate one or more objects (for example, plants) from above orfrom one or more lateral sides of the one or more objects. In someexamples, the light spot illuminated by the light beam in FIG. 5B on aprojection plane comprises two illuminated areas, and the optical systemis configured to illuminate two objects, as is shown in FIG. 2A-2D.

FIG. 5C shows another example of an optical systems illuminating twoobjects from above. The light spot illuminated by the light beam 57 froman optical system 54 on a projection plane 58 comprises a firstilluminated area 501 and a second illuminated area 502, wherein eachilluminated area illuminating one plant 55. The centers of the twoilluminated areas 501 and 502 are respectively located on two sides ofthe optical axis 56. The center of the first illuminated area makes anangle α1 relative to the optical axis. The center of the secondilluminated area makes an angle α2 relative to the optical axis.Optionally, α1 can be substantially the same as α2.

In some examples, the ratio of the light energy in the angle rangecorresponding to the gap area 506 between the two illuminated areas 501,502 to the total energy of the light beam 57 does not exceed 20%. In atleast one example, the light energy in this angle range is substantiallyzero. In at least one example, this angle range is a range of less than15 degrees relative to the optical axis 56.

In at least one example, each of the illuminated areas 501, 502 isrespectively located on both sides of the optical axis 56 and issymmetrical about the optical axis 56. In an example, the correspondingangle range of each illuminated area is from about 15 degrees to about75 degrees with respect to the optical axis, and the center of eachilluminated area makes an angle of about 45 degrees relative to theoptical axis.

FIG. 5D shows an example of a light intensity distribution pattern ofoptical system in FIG. 5C and/or in FIG. 2A-2D. The optical system 54can have an FWHM angle about 150 degrees in a first transverse direction(for example, transverse direction 503 in FIG. 5C), and can have an FWHMangle about 40 degrees in a second transverse direction (for example,transverse direction 504 in FIG. 5C or the vertical direction in FIG.2A-2D) perpendicular to the first transverse direction. The lightintensity increases from a direction pointing to the center of eachilluminated area to the periphery in the first transverse direction andthe second transverse direction.

FIG. 5D is an idealized light intensity distribution of optical system.FIG. 5E shows a realistic example of a light intensity distributionpattern of optical system. The rising and falling edges in the lightintensity distribution pattern are slower comparing to the lightintensity distribution pattern in FIG. 5D.

The light intensity distribution and/or the optical power densitydistribution described above take the light beam from the optical systemas example. In some examples, the light intensity distribution and/orthe optical power density distribution described above can also be thelight intensity distribution and/or the optical power densitydistribution of light of any wavelength from the optical system. In someexamples, the light intensity distribution and/or the optical powerdensity distribution described above can also be the light intensitydistribution and/or the optical power density distribution of light ofany light source in the optical system.

In some examples, optical axis of light beam from each light source (forexample, LED) in the optical system are parallel to each other, andparallel to the optical axis of the optical system. In some examples,the optical system includes a first LED array and a second LED array.The light beam from the optical system comprises the light beam from thefirst LED array and the light beam from the second LED array. Opticalaxes of LEDs in the first LED array are substantially parallel to eachother. Optical axes of LEDs in the second LED array are substantiallyparallel to each other. Optical axis of the first LED array and opticalaxis of the second LED array have an angle with each other. Optionally,the optical axis of the first LED array and the optical axis of thesecond LED array make an angle of about twenty (20) degrees (°) to aboutone hundred twenty (120) degrees (°) between each other. Optionally,both of the optical axes of the first and second LED array have acertain angle relative to the optical axis of the optical system.Optionally, the certain angle ranges from about ten (10) degrees (°) toabout sixty (60) degrees (°). In some application scenarios, the firstLED array is used to illuminate one plant and the second LED array isused to illuminate another plant.

In some examples, the light intensity distribution and/or the opticalpower density distribution described above can also be the lightintensity distribution and/or the optical power density distribution oflight of any LED array in the optical system.

In some examples, the light intensity distribution and/or the opticalpower density distribution of light of any LED array or any light sourcein the optical system can be different from the light intensitydistribution and/or the optical power density distribution describedabove. For example, the light beam from any LED array or any lightsource can have an FWHM angle of less than 120 degrees in sometransverse directions or in all transverse directions. However, thelight beam from all LED array or all light sources are combined to alight beam having the light intensity distribution and/or the opticalpower density distribution described above.

The optical system of the present disclosure has a variety ofconfigurations. For example, the optical system can be created usinglight-emitting diodes (LEDs) with lenses, shaped substrate LEDs, orshaped emitter layer LEDs with overlapping optical power densitypatterns. In some examples, each lens, shaped substrate or shapedemitter layer in the optical system can be configured to emit light witha high light efficiency. Furthermore, each lens, shaped substrate orshaped emitter layer in an optical system can be shaped to create alight distribution pattern of any kind. It is understood that LED can bereplaced by other light sources.

The lens output surface can have kinds of shape. In some examples, thelens output surface is a surface of revolution formed by rotating thelens profiles in the figures described below about a rotational symmetryaxis, wherein the rotational symmetry axis is parallel to the opticalaxis of the LED. Thus, the light spots illuminated by the LEDs in theseexamples are circular, elliptical, close to circular or similar toelliptical.

In some examples, the lens output surface is a surface of translationformed by partially panning the lens profiles in the figures describedbelow respectively along a symmetry axis perpendicular to the opticalaxis of the LEDs. Thus, the light spots illuminated by the LED arerectangular or similar to rectangular.

In some examples, the lens output surface is a free-form surface, andthe lens profiles in the figures described below are different examplesof one profile belonging to the multiple profiles of the lens.

FIG. 6 shows a cross-sectional view of a lens profile 600 and a LEDprofile 602. The lens profile 600 has a substantially concave section603 at the optical axis of the LED, and has two substantially convexsections 604 located at two opposite sides of the concave section 603.In order to provide much higher light intensity at greater angles, thelens 600 both reduces the intensity at small angles and increases theintensity at large angles. The concave central section 603 diverges theLED small-angle rays to relatively larger-angle exit rays, and the twoconvex outer sections 604 converge the LED rays close to 90 degrees torelatively smaller-angle exit rays.

In some examples, a transparent material can be filled between the LED'semitting surface and the lens to eliminate the air gap, which can reducethe Fresnel loss of light at the air-lens interface and at the air-LEDinterface. The transparent material can be silica gel, inorganic geland/or some other materials having a refractive index greater than 1.4.

FIG. 7 shows a cross-sectional view of another lens profile 700 and LEDprofile 702. The side opposite to the light exit surface 703 of the lens700 includes a dome cavity 704, and the surface of the dome cavity 704forms the lens entrance surface. The lens entrance surface has asubstantially concave section 706 at the optical axis 701 of the LED,and has two substantially convex sections 707 located at both sides ofthe concave section 706.

Rays emitted from the LED are shaped by the lens. In order to providemuch higher light intensity at greater angles, the lens both reduces theintensity at small angles and increases the intensity at large angles.The concave central section diverges the LED small-angle rays torelatively larger-angle exit rays, and the convex outer sectionsconverge the LED rays close to 90 degrees to relatively smaller-angleexit rays.

A primary optics element can be further disposed between LED and thelens. The primary optics element can be a refraction lens, a totalinternal reflection (TIR) lens, a hollow CPC, a solid CPC, or areflector. The primary optics element can improve light outputefficiency of the LED, and converge the light emitting angle of the LED.Optionally, the light entrance surface of the lens can include a domecavity that fits over the primary optics element.

FIG. 8 shows a cross-sectional view of another lens profile 800, theprimary optics element profile 805 and LED profile 802. The lens has alight entrance surface 803 opposite to a light exit surface 804. Thelight entrance surface 803 can include a dome cavity 801 that fits overthe primary optics element. Likewise, a transparent material can befilled between the primary optics element and the lens. In FIG. 7, theprimary optics element can be disposed in the dome cavity 704.

FIG. 9 shows a cross-sectional view of another lens profile 903, theprimary optics element profile 902 and LED profile 901. The primaryoptics element disposed between LED and the lens is a CPC. In someexamples, the CPC sidewall is a side wall of revolution formed bypartially rotating the primary optics element profile 902 about arotational symmetry axis, wherein the rotational symmetry axis isparallel to the optical axis of the LED 901. In some examples, the CPCsidewall is a side wall of translation formed by partially panning theprimary optics element profile 902 about a symmetry axis, wherein thesymmetry axis is perpendicular to the optical axis 904 of the LED 901.The CPC is configured to collect the large-angle light emitted by theLED to form a light beam with a small angle. The outgoing beam from CPCis further shaped by the lens 903. The CPC can or can not be removablyconnected to the lens.

FIG. 10 shows a cross-sectional view of another lens profile 1000 andthe primary optics element profile 1001. The primary optics element 1001is a CPC. In some examples, the lens output surface is a surface ofrevolution formed by rotating the profile 1000 about a rotationalsymmetry axis, wherein the rotational symmetry axis is parallel to theoptical axis of the LED.

The lens profile 100 has one or more cusps 1003. Each cusp 1003 willcause the light incident on the cusp 1003 to deflect to two oppositesides of the cusp 1003, forming a low light intensity in the directionof the cusp. In some examples, the lens profile can have three cusp, thefirst cusp is located at the optical axis of the LED, and the other twoare located at two opposite sides of the first cusp, having a certainangle with the optical axis of the LED. The cusp can be an intersectionof a generally concave section and a generally convex section on theprofile 1000, or can be an intersection of a generally concave sectionand a generally concave section on the profile 1000, or can be anintersection of a generally convex section and generally a convexsection on the profile 1000.

In FIG. 10, the lens profile 1001 has a cusp 1003 at the optical axis ofthe LED. The cusp 1003 is an intersection of a generally convex section1004 and a generally convex section 1005. Optionally, the lens profile1001 further has a concave section 1006 at a first direction having afirst angle to the optical axis of the LED, and has a concave section1007 at a second direction having a second angle to the optical axis ofthe LED. Each concaves section is located between two convex sections.This would cause a lower light intensity in the first direction and thesecond direction.

FIG. 5B can be an example of a light intensity distribution pattern oflight emitted from lens of FIG. 10 in the transverse directions that thelens profile 1001 lies. Rays emitted from the LED incident on theconcave sections and the cusp 1003 are diverged, and rays emitted fromthe LED incident on the convex sections are converged. Light intensitytroughs occur respectively around the first direction, the seconddirection and the optical axis of the LED. Light intensity crests occuraround the directions of the convex sections. In a specific example, thefirst direction has a −45 degrees angle with the optical axis of theLED, the second direction has a 45 degrees angle with the optical axisof the LED.

FIG. 11 shows an example of a LED 1103, a primary optics element 1105and a lens. In some example, the lens exit surface 1101 is a surface oftranslation formed by partially panning the profile 600 of lens in FIG.6 along a symmetry axis, wherein the symmetry axis is perpendicular tothe optical axis of the LED 1103. In some examples, the lens exitsurface 1101 is a free-formed surface.

The lens exit surface has a concave section 1102 at the optical axis ofthe LED, and has two convex sections 1104 located on two opposite sidesof the concave section 1102 respectively. Rays emitted from the LED areshaped by the lens. In order to provide much higher light intensity atgreater angles, the lens both reduces the intensity at the concavesection and increases the intensity at the convex section.

In FIG. 11, The primary optics element 1105 is a CPC. The CPC can besquare, or has other shapes. The CPC can emit a light beam havingdifferent divergence angles in different transverse directions. In someexamples, the light beam emitted from the CPC has a first angle in afirst transverse direction, and has a second angle in a secondtransverse direction, wherein the first angle is less than 0.8 times thesecond angle.

In some examples, the primary optics element can be removable. In someexamples, the primary optics element can or cannot be removablyconnected to the lens. FIG. 12 shows another example of a lens 1200 anda CPC 1201. The CPC is integrated with the lens, thus reducing two airinterfaces and reducing the Fresnel loss of light.

While preferred examples of the present disclosure have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch examples are provided by way of example only. Numerous variations,changes, and substitutions will now occur to those skilled in the artwithout departing from the disclosure. It should be understood thatvarious alternatives to the examples of the disclosure described hereincan be employed in practicing the disclosure. It is intended that thefollowing claims define the scope of the disclosure and that methods andstructures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. An optical system for facilitating plant growth,comprising: one or more light sources operable to produce a light beamhaving a full width at half-maximum (FWHM) angle of at least one hundredtwenty degrees(120°) in at least one transverse direction; wherein theat least one transverse direction is perpendicular to an optical axis ofthe light beam wherein a light spot illuminated by the one or more lightsources on a projection plane includes a gap area having a minimumoptical power density, wherein the gap area is located at an angleapproximately less than fifteen degrees) (15°) relative to the opticalaxis.
 2. The optical system of claim 1, wherein the FWHM angle isbetween one hundred twenty degrees(120°) and one hundred sixty degrees(160°) in the at least one transverse direction.
 3. An optical systemfor facilitating plant growth, comprising: one or more light sourcesoperable to produce a light beam having a full width at half-maximum(FWHM) angle of at least one hundred twenty degrees(120°) in at leastone transverse direction; wherein the at least one transverse directionis perpendicular to an optical axis of the light beam, wherein the oneor more light sources are operable to produce the light beam having anFWHM angle of greater than one hundred twenty degrees (120°) in a firsttransverse direction, and having an FWHM angle of less than one hundredtwenty degrees (120°) in a second transverse direction, wherein thefirst transverse direction and the second transverse direction areperpendicular to each other.
 4. The optical system of claim 3, whereinthe FWHM angle in the first transverse direction is greater than onehundred thirty degrees (130°) and the FWHM in the second transversedirection is less than eighty degrees (80°).
 5. The optical system ofclaim 4, wherein the FWHM angle in the second transverse direction isless than fifty degrees (50°).
 6. The optical system of claim 4, whereinthe one or more light sources are operable to illuminate one or moreplants in a lateral direction, with the first transverse direction alongone or more lateral sides of the one or more plants.
 7. The opticalsystem of claim 6, wherein the one or more light sources are operable toilluminate the one or more plants obliquely vertically, with an anglebetween an optical axis and a horizontal plane being greater than tendegrees (10°).
 8. The optical system of claim 7, the angle between theoptical axis and the horizontal plane is greater than half of the FWHMangle in the second transverse direction.
 9. The optical system of claim1, wherein an optical power density in the light spot illuminated by thelight beam on the projection surface at a distance from the one or morelight sources is substantially uniform.
 10. The optical system of claim9, wherein the projection surface is a surface of a conical body or aplane.
 11. The optical system of claim 1, wherein an average opticalpower density in an intermediate region in a light spot illuminated bythe one or more light sources is equal to or less than average opticalpower density in a first region, wherein the first region is an annularregion surrounding the intermediate region in the light spot.
 12. Theoptical system of claim 11, wherein in at least one transversedirection, the light intensity of light increases from the optical axisto the periphery.
 13. The optical system of claim 12, wherein in the atleast one transverse direction, light intensity distribution of thelight beam I(θ) is substantially equal to I₀/cos³(θ), where I₀ is thelight intensity of the light at the optical axis and I(θ) is the lightintensity of the light beam having an angle θ relative to the opticalaxis.
 14. The optical system of claim 12, wherein average optical powerdensity in the intermediate region is a global minimum in the lightspot.
 15. An optical system for facilitating plant growth, comprising:one or more light sources operable to produce a light beam having a fullwidth at half-maximum (FWHM) angle of at least one hundred twentydegrees (120°) in at least one transverse direction; wherein the atleast one transverse direction is perpendicular to an optical axis ofthe light beam, wherein a light spot illuminated by the light beam on aprojection plane comprises two or more illuminated areas, wherein eachilluminated area illuminating one plant.
 16. The optical system of claim15, wherein a light intensity distribution for each illuminated area hasa trough and two crests located on opposing sides of the trough in atleast one transverse direction, wherein the trough is located at alongitudinal direction having an angle θ with respect to the opticalaxis.
 17. The optical system of claim 16, wherein angle θ is about fortyfive degrees (45°).
 18. The optical system of claim 16, wherein one ofthe two crests is located at a longitudinal direction having an angle aof about seventy five degrees (75°) with respect to an optical axis, andthe other crest is located at a longitudinal direction having an angle βof about fifteen degrees (15°) with respect to the optical axis.
 19. Theoptical system of claim 18, wherein the average optical power density ina gap area between two adjacent illuminated areas is less than a minimumoptical power density in the illuminated areas.
 20. The optical systemof claim 19, wherein a ratio of light energy in the gap area between thetwo adjacent illuminated areas to total energy of the light beam is lessthan twenty percent (20%).
 21. The optical system of claim 20, whereinthe gap area between the two adjacent illuminated areas corresponds toan angle of less than thirty five degrees (35°).
 22. The optical systemof claim 1, wherein the one or more light sources includes a first LEDarray and a second LED array, an optical axis of the first LED array andan optical axis of the second LED array are in different directions. 23.The optical system of claim 22, wherein the optical axis of the firstLED array and the optical axis of the second LED array form an anglebetween twenty degrees (20°) and one hundred twenty degrees (120°). 24.The optical system of claim 22, wherein the optical axis of the firstLED array and the optical axis of the second LED array form an angle yrelative to the optical axis of the one or more light sources.
 25. Theoptical system of claim 24, wherein the angle γ ranges from ten degrees(10°) to sixty degrees (60°).
 26. The optical system of claim 1, whereinthe light beam has spectra including blue wavelengths and redwavelengths.
 27. The optical system of claim 1, wherein the one or morelight sources comprises at least one light source of the one or morelight sources operable to emit a light beam having differentwavelengths, and the at least one light source operable to emit a lightbeam having different wavelengths are controllable individually.